1. Field of the Invention
The invention relates to a sensor system which is not connected by wire (“wire-free”), to a monitoring system based on this sensor system, and to two uses of the sensor system.
2. Description of the Related Art
Until now, environmental changes have mainly been detected by sensors which pass on state information via wire lines, and are at the same time supplied with electrical power via these wire lines. The wiring, which is often complex and thus costly, is problematic in this case.
Battery-operated sensors are likewise known, which pass on the corresponding measured values by radio. However, these have the disadvantage that the batteries must be serviced. Particularly where there are a large number of devices to be monitored, the batteries cause logistic problems for servicing, as well as high costs.
DE 198 26 513 A1 (which corresponds to US Patent Application Publication No. 2001/003163) discloses an automation system for control of a processing apparatus having a radio sensor which is used to reduce the installation complexity. For this purpose, it has a radio sensor which can be operated by means of a solar cell, possibly in conjunction with an energy store.